package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();

        records.forEach(blog -> {
            // 查询用户
            this.queryBlogUser(blog);
            // 查询当前用户是否已经点赞
            this.isBlogLiked(blog);
        });


        return Result.ok(records);
    }

    /**
     * 修改点赞数量
     *  需求:
     *  同一个用户只能点赞一次，再次点击则取消点赞
     *  如果当前用户已经点赞，则点赞按钮高亮显示（前端已实现，判断字段Blog类的isLike属性）
     * @param id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();

        //2.判断当前登录用户是否已经点赞
        String key= BLOG_LIKED_KEY + id; //博客id
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());

        if (score == null){
            //3.如果未点赞，可以点赞
            //3.1 数据库点赞 liked + 1
            boolean isSuccess = update().setSql("liked = liked +1").eq("id", id).update();
            //3.2 保存用户到Redis的set集合  zadd key value score
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞 liked -1
            boolean isSuccess = update().setSql("liked = liked -1").eq("id", id).update();
            //4.2 把用户从Redis的set集合移除
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 查询点赞top5的用户
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {

        String key= BLOG_LIKED_KEY + id;
        //1.查询top5的点赞用户  zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5== null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }

        //2.解析出用户id查询用户
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idsStr = StrUtil.join(",", ids);
        //3.根据用户id查询用户 where id in (?,?) order by field(id,?,?)
        Stream<UserDTO> UserDTOS = userService.query()
                .in("id",ids).last("order by field(id,"+idsStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class));

        //4.返回
        return Result.ok(UserDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 2.保存探店博文
        boolean isSuccess = save(blog);
        if (!isSuccess){
            return Result.fail("新增笔记失败!");
        }
        // 3.查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();

        // 4. 推送笔记id给所有粉丝
        for (Follow follow : follows) {
            //4.1 获取粉丝id
            Long userId = follow.getUserId();
            //4.2 推送
            String key=FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }

        // 5.返回id
        return Result.ok(blog.getId());
    }

    /**
     * 滚动分页查询
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogFollow(Long max, Long offset) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.查询收件箱  ZREVRANGEBYSCORE key max min LIMIT offset count
        String key =FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 3);
        //3.非空判断
        if (typedTuples== null || typedTuples.isEmpty()){
            return Result.ok();
        }

        //4.解析数据 blogId、score（时间戳）、offset(跟上次查询的最小值一样的元素的个数)
        List<Long> ids=new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os=1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            //4.1获取id
            ids.add(Long.valueOf(tuple.getValue()));

            //4.2获取时间戳
            long time = tuple.getScore().longValue();

            if (time== minTime){
                os++;
            }else {
                minTime = time;
                os=1;
            }
        }

        //5.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id",ids).last("order by field(id,"+idStr+")").list();

        for (Blog blog : blogs) {
            //5.1查询blog相关的用户
            queryBlogUser(blog);
            //5.2查询blog是否被点赞
            isBlogLiked(blog);
        }

        //6.封装并返回
        ScrollResult result=new ScrollResult();
        result.setList(blogs);
        result.setMinTime(minTime);
        result.setOffset(os);

        return Result.ok(result);
    }

    /**
     * 是否点赞当前博客
     * @param blog
     */
    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user==null){
            //用户未登录，无需查询或点赞
            return;
        }
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前登录用户是否已经点赞
        String key= BLOG_LIKED_KEY+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key,userId.toString());
        blog.setIsLike(score!=null);
    }

    @Override
    public Result queryBlogId(Long id) {
        //1.查询 blog
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("笔记不存在");
        }
        //2.查询blog 相关用户
        queryBlogUser(blog);
        // 3.查询bolg是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }


    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }



}
